The addition of hyperbaric oxygenation to a specialised wound care program for chronic diabetic foot ulcers resulted in improved survival, healing and quality of life.

Clinical bottom line:

1. The addition of hyperbaric oxygen therapy improved the proportion of diabetic wounds that healed at one year.
2. The adverse event rate was low.


1. Londahl M, Katzman P, Nilsson A, Hammarlund C. Hyperbaric oxygen therapy facilitates healing of chronic foot ulcers in patients with diabetes. Diabetes Care 2010;33(5):998-1003.

2. Londahl M, Katzman M, Nilsson A, Hammarlund C, Sellman A, Wykman A. Hugo-Persson M, Apelqvist J. A prospective study: hyperbaric oxygen therapy in diabetics with chronic foot ulcers. Journal of Wound Care 2006;10(15):457-459.

3. Londahl M, Ladin-Olssen M, Katzman P. Hyperbaric oxygen therapy improves health-related quality of life in patients with diabetes and chronic foot ulcer. Diabetic Medicine 2011;28:186-190.

4. Londahl M, Katzman P, Hammarlund C, Nilsson A, Landin-Olssen M. Relationship between ulcer healing after hyperbaric oxygen therapy and transcutaneous oximetry, toe blood pressure and ankle–brachial index in patients with diabetes and chronic foot ulcers. Diabetologia 2011;54:65-68.

5. Londahl, M ; Fagher, K ; Nilsson, AL ; Katzman, P. Diabetologia, Improved 6-year survival in patients with chronic diabetic foot ulcers afterhyperbaric oxygen therapy: outcome from a randomised double-blind study. 2015 Sep, Vol.58 Suppl 1, pp.S31-S31

6. Fagher K, Katzman P, Löndahl M. Hyperbaric oxygen therapy reduces the risk of QTc interval prolongation in patients with diabetes and hard-to-heal foot ulcers. Journal of Diabetes and its Complications. 2015 Dec 31;29(8):1198-202.

7. Sellman A, Katzman P, Andreasson S, Lõndahl M. Long-term effects of hyperbaric oxygen therapy on visual acuity and retinopathy. Undersea & hyperbaric medicine: journal of the Undersea and Hyperbaric Medical Society, Inc. 2020 Jan 1;47(3):423-30

Lead author's name and fax: Magnus Londahl [magnus.londahl@med.lu.se]

Three-part Clinical Question: For diabetic patients with chronic lower limb ulcers, does the additon of hyperbaric oxygenation to a specialised wound care protocol, result in an improved rate of healing?

Search Terms: Diabetes, chronic wound, skin ulcer

The Study:Double-blinded concealed randomised controlled trial with intention-to-treat.

The Study Patients: Adult diabetic patients with ankle or foot ulcers for more than 3 months (including 2 months of specialised wound care) and where there is no major vessel disease requiring surgical intervention.

Control group (N = 45; 42 analysed): Specialised, comprehensive wound care plus 40 hyperbaric treatments breathing air at 2.5 ATA for 90 minutes daily Monday to Friday over 8 to 10 weeks.

Experimental group (N = 49; 48 analysed): As above, but breathed 100% oxygen at 2.5 ATA for 90 minutes daily on same schedule as the sham.

The Evidence:


Time to Outcome

Sham rate

HBOT rate

Relative risk reduction

Absolute risk reduction


Wound healed

1 year







95% Cls:

20% to 162%

.05 to 0.43

2 to 19


1 year







95% CIs:

54% to 100%

0.04 to 0.13

NNT 8 to INF

NNH 28 to INF

Major amputation

1 year







95% CIs:

100% to 549%

0.04 to 1.21

NNT 25 to INF

NNH 8 to INF

Visual substudy


Time to Outcome

Control group

HBO group

Relative risk reduction

Absolute risk reduction


Loss of 10 or more letters on visual acuity testing

3 months






95% CIs:


-0.20 to 0.01

NNT = 141 to INF;

NNH = 5 to INF

New macular oedema

2 years






95% CIs:

-182% to 100%

-0.18 to 0.13

NNT = 8 to INF;

NNH = 5 to INF


Kaplan-Meier survival over six years (Per-protocol analysis): Sham survival at six years 42% versus HBO group 68%, P = 0.026


1. Well conducted study with high methodological rigour and a low risk of bias.

2. Quality of life was assessed at one year using the SF-36 questionnaire over eight dimensions. Those who received HBOT improved statistically significantly in two dimensions (physical functioning and emotional state), while those receiving sham had not significantly improved.

3. Baseline transcutaneous oxygen levels correlated positively with the chance of healing in those who received HBOT. Neither toe blood pressures nor ankle-brachial index at baseline predicted healing.

4. A per protocol analysis of those who received at least 35 treatment or sham sessions confirmed a benefit from HBOT (61% healing versus 27% healing at one year, P = 0.009).

5. A second per protocol analysis of 73 patients (38 HBO, 35 sham) was conducted looking at the change in QT corrected for heart rate on ECG over the course of treatment. QTc time was significantly shorter in the HBO group as compared to the placebo group, 438 (425–453) vs. 456 (424– 469) ms, p < 0.05. This difference seemed to be caused by a significant prolongation of the QTc interval in the placebo group.

6. Visual substudy on 50 participants suggested early transient reduction in VA (at three months) but not at later assessment. No group differences in any retinopathy. No evidence of negative consequences from therapy.

Appraised by: Mike Bennett, POWH, Sydney; Thursday, 19 April 2012Email: [m.bennett@unsw.edu.au]

Kill or Update By: September 2024